Almost every TV used to be without a mains transformer. Plastic cabinet. When a power line transient hit, look out! I had an old Hitachi. First time I fixed a half dozen parts. Second time everything save the HT was toasted. They relied on the polarized plugs and even worse, that your house was correct and you did not have an extension cord that had wide slots. I am sure CSA would have fits today. Even UL might.

Transformerless power supplies are dangerous! DO NOT DO! Even an experienced person must not do this. There are a lot of other people around. Also, mains can proliferate to the guitar humbucker and no one knows how this will weld. The least bad would be like in the Hollywood Movies and a hair style like Dr. Ainstain.

Again: I APPOLOGISE TO ALL. I DID NOT KNOW. I WILL NEVER POST SIMILAR.

PLEASE, NOTE: SUCH TRICKS ARE VERY DANGEROUS IN EUROPE AND EXTREMELY DANGEROUS IN THE UK WITH 250V RMS MAINS.

In cases where step up power factor correction is used,
do forum rules allow for isolation to be located on the
step down side? Most PC power supplies and bricks fall
into this category. But we are talking DIY... Yes, no,
only in an insulated or grounded separate enclosure?

I would like to suggest a topic for discussion but, please, do NOT post specifics which may lead to design ideas, due to the sensitivity of the topic.

Do you not believe UL and CSA should approve designs with this idea, at least when manufactured by top companies under strict regulations only, such as Motorola for example. I insist on the word ONLY. I do not care what the politics is, I am interested in being able to purchase such, hopefully for a regulated kinda fair price, and I do NOT want political stupidities to stop this only. So, I will be happy a monopoly to be given to one company only under approved design. This is protection monopoly and not protectionism monopoly. Protection from electrocution, this is.

Ideally, such has to be carried by a state owned enterprise but when US government hears the combination of this words they jump sky high to Mars, to the red planet of the universe and start blowing iron curtains.

Anyways, I have been talking of alternative protection, mainly electronics protection with current and voltage sensing, for example. Power electronics devices rated 10 even 100 factor higher than the parameters of a given device can establish a good level of protection. Some of them can straight connect the mains and withstand for a sufficient amount of time for the fuses or circuit breakers to blow up or switch off.

Officials are afraid the electronic devices are unreliable and may get welded in an unpredictable way thus electronics protection may be unreliable.

Then I would like to ask you all this question: HOW SAFE IS A TRANSFORMER? HOW SAFE IS A WOUND WIRE WITH LAQUER?

Yes, you would answer the transformer has two coils: a primary and a secondary which are totally isolated and there is no way the primary to blow up and the mains to be transferred to the secondary. Either works OK or doesn't work at all, in either case we are all safe.

Then imagine an American goes to the UK and gets a transformer to convert 250V, 50Hz to, say, 175V, 50Hz ( more power than 120, 60Hz ). Assume, there are many outputs (or many secondary coils) with many voltages. Assume high power output. So, when the secondary gets melted and welded and 175V, 50Hz is applied all over the place, is this OK?

An alternative is to assume Americans is allowed to fry in the UK but not allowed in their own country.

So, do you not think electronics may be considered reliable enough to be used for protection purposes or at least a mechanical relay.

Another question: Do you believe DC power can be supplied directly from the power plant or at least from the nearby transformer with different voltages and high currents (high power DC sockets)?

AC can be converted to DC not only by huge power electronics but also by electromechanical means.

Since you've chosen to continue down a path of advocating deadly dangerous practice without apparently understanding the safety issues, this thread is closed. Do not go there again- the rules are in place for a reason and your energy is better expended learning about basic electronics safety.

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"Pity, wrath, heroism, filled them, but the power of putting two and two together was annihilated."- EM Forster